Air seeders and other seeding devices are commonly towed by tractors to apply seed or fertilizer, or both simultaneously, to a field. As an example, an air seeder may be towed in combination with a tilling implement, one behind the other, to place the seed and fertilizer under the surface of the soil. An air seeder has as its central component a wheeled seed cart which comprises one or more frame-mounted product tanks for holding product, generally seed or fertilizer or both. Air seeders also generally comprise a metering system for dispensing product from the tanks and a pneumatic distribution system for delivering the product from tank to soil.
It is known to provide an air seeder with volumetric meters which measure a fixed volume of seed per unit of linear distance. These volumetric meters typically comprise either augers or fluted cylinders (meter rollers) which rotate through a product reservoir to measure granular product, as illustrated in U.S. Pat. Nos. 3,489,321 and 3,763,797. The meters rotate to feed product into a pneumatic distribution system. The pneumatic distribution system of an air seeder generally utilizes a centrifugal fan to provide at least one airstream which flows through the pneumatic distribution system to seed boots where product is deposited in the soil. Product is first introduced to the air stream by the metering system at a primary distribution manifold located below the metering system. Product is carried by the air stream through distribution lines to a series of secondary distribution manifolds ("headers"), which in turn distribute product through distribution lines to seed boots mounted behind ground openers on the tilling implement so that the product may be evenly delivered to the span of ground (the "tillage") acted upon by the tilling implement.
Operators of conventional seeding equipment are generally unable to remove metering system components (e.g., for inspection, repair or replacement) without first emptying the product tank which services the metering system. In air seeders in particular, emptying the large central product tanks is cumbersome and time consuming. On conventional seeding equipment which does allow an operator to shut off product to the metering system, the operator is unable to empty the product tank without sending product through the metering system. For example, U.S. Pat. No. 4,834,004 discloses slides which may be used to shut off product to a metering system. The slides move horizontally and do not provide a means to remove product from the product tank other than allowing the product to flow through the metering system.
In addition, operators of conventional seeding equipment are unable to shut off product flow to a portion of the metering system such that, during operation, product is delivered to only a portion of the tillage.
Therefore, it is desirable to devise a product disconnect which can substantially shut off product flow from a product tank to a metering system in a piece of seeding equipment.
It is also desirable to devise a product disconnect having a plurality of cutoffs which are selectively engageable to shut off product flow to a portion of the metering system to achieve a desired product distribution across the tillage.